I need to run the yum update on my Linux redHat machine

during the yum update , I sow that yum perform some patch kernel update

therefore I little worry to perform a reboot , because the patches of the kernel update

I need advice what I need to verify or configure regarding the patches of the kernel update , in order to start up normally my Linux machine


Two things to keep in mind with RHEL (which is what I'm assuming you mean by "red hat"):

1) It's an Enterprise platform, which means they intentionally try to keep things as similar as possible for as long as possible. The updates you're getting are to fix issues with the older kernel. Occasionally they'll backport new features or rebase a package but the goal is to change as little as humanly possible. This is why they had to create thing like software collections. People kept complaining that the software versions on RHEL were getting very old by the time a platform was halfway through its lifecycle.

2) You're allowed more than one kernel to be installed, for the exact reason you're worried about the update. The default is to keep the current kernel and the two previous kernel installed and available as alternative boot options. If the new kernel creates issues for you, just force a reboot and select one of the older kernels next time. Once you figure out what the issue was with the new kernel (hardly ever happens to begin with, but it's usually some proprietary software being in the initrd) you can remediate and reboot as appropriate.

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  • thx for your answer - but regarding you second step -2 , can you please give example about , the kernel PATH ( location ) , how to backup the kerrnel in case it will be new one and etc ... , after patch kernel update what are the steps that I need to do in case of next reboot failure – yael May 8 '16 at 21:14
  • @yael the grub screen at boot up lets you choose whatever kernel is available on the system at the time. There's no such thing as "backing up" a kernel when RHEL defaults to having 3 kernels installed at once. It's like that for scenarios where hardware or other unforeseen issues occur with a kernel patch. – Sokel May 8 '16 at 21:21
  • @yael you don't really need to back up the kernel since you're allowed to have more than one. Really the only thing that could possibly break would be the grub config file. You can just copy the /boot/grub/grub.conf or /boot/grub2/grub.cfg (depending on the version of RHEL). I've never had it mess up my grub config, though. Most of the kernel stuff is in /boot/(vmlinuz*|initramfs*) and /lib/modules/<kernel version> though. – Bratchley May 8 '16 at 21:26
  • It really sounds like you're overcomplicating this in your mind, though. The kernel is probably one of the safer packages to update since there are so many ways to rollback with minimum fuss. Unless you're doing something exotic with the kernel, it's almost certainly going to work without issue. Maybe it would help to not think of it as "updating" a kernel, so much as installing a new one and occasionally yum will remove kernel that are way old and you don't use anymore. – Bratchley May 8 '16 at 21:31
  • ok , I will backup the grub.conf , second - where are the files - vmlinuz.... and initrd..... in the linux redhat machine ? – yael May 8 '16 at 21:34

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